1. The Field of the Invention
This invention relates to magnifying devices and filling indicating apparatus useful with hypodermic syringes and more particularly to that class adapted to be transferred from syringe to syringe at the will of the user.
2. Description of the Prior Art
The prior art abounds with magnifying devices suitable for use with medical apparatus. U.S. Pat. No. 3,855,866 issued Dec. 24, 1974 to J. F. Klinger et al teaches a readout device for use with a thermometer for facilitating determination of the thermometer reading and also to retain the determined indication notwithstanding a subsequent change in the indicator reading. The readout means may define a magnifying lens for facilitating the readout and includes resilient gripping means for retaining the readout means adjustably on the thermometer stem. A readout means may be adjusted while the thermometer is in the patient's body orifice. The thermometer includes a metal bulb secured to one end of the stem to provide a sealed connection therewith. This apparatus provides an indicia line associated with the magnifying lens so as to increase the capability of determining the readout at a later point in time, following taking the temperature of the patient's body. Such apparatus however, is secured to the thermometer in a pseudopermanent manner thereby precluding its use with disposable medical instruments.
U.S. Pat. No. 3,052,158 issued Sept. 4, 1962 to A. W. Sonni discloses a combination of a clinical thermometer and a magnifying case. A case is provided, being fabricated from a transparent material and having a convex lens portion comprising a portion of the walls thereof. A thermometer may be inserted within the case in a preferred location, capped therein by a removable cap portion so as to selectively position the readout scale of the thermometer below the magnifying portion of the case. In use, the patient's temperature is first taken; the thermometer is then stored within the case so as to permit the user to more conveniently read the readout scale of the thermometer. However, such apparatus requires that the thermometer be removed after use for cleaning purposes before the apparatus is stored therewithin again. The means required to position the readout scale at the preferred angular relationship to the magnifying portion of the case requires careful alignment and hence makes such apparatus difficult to use.
U.S. Pat. No. 2,389,282 issued Nov. 20, 1945 to R. F. E. Steggman describes a convex lens portion having a pair of outwardly extending wings from the end thereof, each wing-like portion is provided with a hole. Both holes are coaxially aligned and adapted to frictionally engage the side thermometer. In use, the magnifying portion of the apparatus defined between the wing portions thereof, is positioned over the readout scale of the thermometer. Such lens portion may be moved to preferential locations so as to facilitate the reading of the thermometer apparatus. The Steggman disclosure, however, though providing an indicia line extending transverse to the length of the thermometer, fails to position the magnifying device in a convenient referenced fashion to a preferred location along the length of the medical device on which it is employed. Thus, Steggman, as well as the aforementioned other patents, each fail to teach an apparatus which enables the user to adjust some function of the device employing the same to a preset level. Rather, these apparatuses simply allow the user to readout a function presented to the apparatus, namely the level of mercury indicative of body temperature.